Disclosed is a surface light source device suitable for backlighting film images in film scanner. The surface light source device comprises: a light source for emitting a light toward an optical path; a first reflector provided so that a reflective surface of said first reflector is vertical to the optical path; a second reflector provided between said light source and said first reflector so that a reflective surface of said second reflector is parallel to the optical path; an exit diffusing plate; and a plate on which a diffusing patter is provided, said plate being provided so as to be tilted with respect to the optical path in a direction such that light from the light source is reflected toward the second reflecting surface.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A surface light source device for emitting a two dimensional light from a light exit, said surface light source device comprising: a light source for emitting a light; a plate having a surface that has both a transparent portion and a diffusing portion, the transparent portion passing a first portion of the light therethrough and the diffusion portion diffusing a second portion of the light, said plate being optically disposed between said light source and said light exit; a first reflector which is provided so that light having passed said plate is reflected by a first reflective surface and the light thus reflected is directed toward said plate again; and a second reflector which is provided so that the light having been diffused by said plate is reflected and the light thus reflected is directed toward said plate again.
2. The surface light source device as claimed in claim 1 , wherein said plate is disposed so as to be inclined with respect to said second reflector.
3. The surface light source device as claimed in claim 1 , wherein said plate is disposed so as to be inclined with respect to said first reflector.
4. The surface light source device as claimed in claim 1 , wherein said light source comprises at least one light emitter having a directivity mainly emitting the light in a predetermined direction.
5. The surface light source device as claimed in claim 4 , wherein said plate is provided so as to be inclined with respect to the predetermined direction.
6. The surface light source device as claimed in claim 5 , wherein said first reflective surface of said first reflector is vertical to the predetermined direction, and so that said plate is located between said light source and said first reflector.
7. The surface light source device as claimed in claim 5 , wherein said second reflector is provided so that a reflective surface of said second reflector is parallel to the predetermined direction, and so that said plate is located between said light exit and said second reflector.
8. The surface light source device as claimed in claim 1 , further comprising: a diffusing plate located at the light exit.
9. The surface light source device as claimed in claim 1 , wherein said plate is a single tilted plate.
10. A surface light source device comprising: a light source for emitting a light toward an optical path; a first reflector provided so that a reflective surface of said first reflector is vertical to the optical path; a second reflector provided between said light source and said first reflector so that a reflective surface of said second reflector is parallel to the optical path; an exit diffusing plate; and a plate having a surface that has both a transparent portion and a diffusing portion, said plate being provide so that a surface of the plate that the light from the light source initially strikes is tilted the second reflector such that light from the light source is reflected toward the reflecting surface of the second reflector.
11. The surface light source device as claimed in claim 10 , wherein said light source, said first reflector, said second reflector, said exit diffusing plate, and said plate are provided in a holder.
12. The surface light source device as claimed in claim 10 , wherein said light source comprises at least one light emitting diode.
13. The surface light source device as claimed in claim 12 , wherein said light source comprises a plurality of light emitting diodes aligned in a direction parallel to a surface of said exit diffusing plate.
14. The surface light source device as claimed in claim 10 , wherein said plate is a single tilted plate.
15. A surface light source device for emitting a two dimensional light from a light exit, said surface light source device comprising: a light source for emitting a light; a plate having a surface that has both a transparent portion and a diffusing portion, the transparent portion passing a first portion of the light therethrough and the diffusion portion diffusing a second portion of the light, said plate being optically disposed between said light source and said light exit; and a first reflector which is provided so that light having passed said plate is reflected by a first reflective surface and the light thus reflected is directed toward said plate again, wherein said plate is disposed so as to be inclined with respect to said first reflector.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
October 4, 1999
December 31, 2002
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